Astrograph Telescopes

For serious astrophotographers, an optical tube that has quality optics and suitable specifications is key to producing successful images. Astrographs come in many different specifications and designs, so each model can be oriented or preferred for a different type of imaging (eg. solar, terrestrial, deep sky etc). Some common designs include the Ritchey-Chrétien, Riccardi Honders, and Catadioptric optical tubes. Choosing an astrograph depends on how the astro-imager wants to observe, what focal length and focal ratio it has, aperture, optical coatings, and how suitable it is for the camera they intend to use.

A key specification very important to consider when choosing an astrograph is focal ratio in relation to aperture. This is an important to remember because focal ratio determines what the magnification and field of view the observor will get. Therefore, if the observor intends to mainly view deep sky objects with lower surface brightnesses, a shorter focal length will reduce magnification and increase field of view since most deep sky objects tend to appear very large but not bright. Astrograph telescopes with slower focal ratios such as an f/12 will provide higher magnification and smaller field of views; better for planetary observing.

The new Takahashi incorporates optics that use an exceptionally advanced design that produces a flat-field astrograph a with large highly illuminated field that is further enhanced with the new dedicated 645 reducer that produces a Ø70mm image circle at f/3.5.

Takahashi introduced their Epsilon Series flat-field hyperbolic astrographs in the middle 1980’s. The Epsilon-130 was the smallest aperture and most portable of the series. Now Takahashi is re-introducing the new ε-130D digital version of this astrograph.

The 12" AG Optical astrograph has a medium focal ratio of f/6.7 and features an RMS spot size of 6 microns which makes for pinpoint images of stars at low field of views. This optical tube has a two element <0.5% reflective corrector which makes this possible by reducing many of the common light distortions such as coma.

The AG Optical 17" iDK Astrograph is an excellent astrograph for a wide variety of astrophotography. The telescope has a medium focal ratio of f/6.7 with 6 micron RMS spot size. This means that stars appear very pinpoint while still at large field of view.

A great benefit behind the Dall Kirkham design is excellent off-axis performance. The 12.5 astrograph from AG Optical is in a carbon fiber tub and has a medium focal ratio with a large aperture to support a variety optical and astrophotography combinations.

Developed by Astro-Tech to make large-format CCD imaging affordable for the amateur astronomer, the Astro-Tech AT10RCF is priced thousands of dollars less than the formerly least-expensive 10” R-C. The Astro-Tech AT10RCF is the first truly affordable large aperture true Ritchey-Chrétien astrograph available from a U. S. company.

Ritchey Chretien astrograph telescopes are exclusively used in many professional fields, including the HST. Astro-Tech has designed a 6" f/9 Astrograph that is based upon this design to the amateur astronomer at affordable prices.

The Officina Stellare Pro RC Series telescopes are made of some of the best quality optics including but not limited to, homogenous blanks of certified origin chosen between borosilicate to Pyrex tot Sitall and other low expansion ceramic glass.

The Officina Stellare Pro RC Series telescopes are made of some of the best quality optics including but not limited to, homogenous blanks of certified origin chosen between borosilicate to Pyrex tot Sitall and other low expansion ceramic glass.